Fixup documentation

1. Adds the gwpy methods as the preferred way to set the strain data
2. Removes references to some of the problematic helper functions
3. Adds a bilby.gw.detector.Interferomer.set_strain_data_from_gwpy_timeseries wrapper for consistency
4. Various minor fixes to other documentation pages

bilby/core/sampler/base_sampler.py

@@ -569,6 +569,7 @@ class NestedSampler(Sampler):
         the prior constraint here.
 
         Parameters
+        ----------
         theta: array_like
             Parameter values at which to evaluate likelihood